It is well known to employ a coherent fiber optic bundle to apply a group of pixels to a sensor array. Such a system employs a fiber for each sensor and requires the attachment (or imaging) of a fiber onto the associated sensor in order to achieve a defect-free image. For large numbers of fibers, particularly when the fibers have very small diameters, the attachment of the fibers to the associated sensors is tedious, difficult, and expensive to achieve.
The above-mentioned copending application discloses a technique not only for achieving a coherent image from a fiber optic bundle, but also by doing so with a non-coherent bundle and by doing it in a manner which eliminates the need for associating each fiber with a corresponding sensor or for predetermining its position ahead of time. Instead, the output end of the fiber optic bundle is associated with a sensor array without regard to the spatial relationship of the fibers and the sensors of the array. But the fiber diameter is chosen to be large compared to the size of a sensor or the fiber exit end is imaged onto the sensor array in a manner to correspond to a plurality of sensors.
An initializing arrangement is used to determine which sensors correspond to a particular fiber of the bundle wherever that fiber may be located in the bundle. The initializing arrangement is adapted to move a beam of radiation incrementally along a path in the input face of the array in a manner to intersect the fibers in an ordered sequence. The beam is incremented along the path such as to intersect the fiber ends and the sensor array is interrogated, in each instance, to determine which sensors are illuminated each time the beam is moved. Because the beam diameter is relatively small, there is no need to move the beam accurately to the precise positions of consecutive fibers in the input face. In this manner, a non-coherent fiber optic bundle is made to provide a coherent image electronically in a simple and inexpensive manner.
The present invention is based on the recognition that the initializing arrangement can be made to serve a benefit for coherent fiber optic bundles as well as non-coherent fiber optic bundles when used as an input to a random access, electronically addressed readout, implemented with a CCD, CID, optic RAM chip, or Vidicon technology. The problems that arise with respect to coherent optical fiber bundles have to do primarily with a mismatch between the diameter or shape of a fiber in the bundle and the size, shape, and/or location of the sensors of the array. The transmitted image is acceptable only as long as the fiber diameter equals the size and location of the sensor to which it is attached. But if a mismatch occurs in size or location, the group of pixels transmitted by the fiber bundle can cause the image to be degraded significantly. Not only is important information lost, but, in addition, many degrading artifacts may occur, such as aliasing and moire patterns.